LOS ANGELES — The policy of the United States, at the moment the world's only superpower, lacks an overall sense of urgency about the spread and possible use of nuclear weapons. In all probability, this lapse will someday lead to immense tragedy.

The world has been sitting on a ticking time-bomb for six decades. It is an inexplicable miracle rather than superior national-security policy or international-control management that a nuclear weapon hasn't exploded on one or more population centers.

Don't, of course, run this superficial observation by the Japanese, who still have the painful memory of Hiroshima and Nagasaki. It is not for nothing that this technologically brilliant but overpopulated nation remains, despite recent militant uptick emotions, on the whole anti-nuclear and pacifist.

But Japan someday will go nuclear if North Korea establishes itself as a palpable nuke power, as with Pakistan and India, a pair of competing nuclear powers. Russia still has piles of nukes; the British and the French have not relinquished their stockpiles; Israel denies — unconvincingly to many — that it has the bomb; Iran denies — equally unconvincingly to many — any intention of developing a nuclear capability. And so it goes.

The U.S. takes the prize, though. It maintains (on 24-hour alert, hair-trigger status, no less) more than 10 times (at least) as many nuclear warheads as there are nations in the world. This absurd and risky overreadiness has drawn new fire here from warriors old and new.

The late President Ronald Reagan, though anything but a dove while in office, appears to have been a passionate nuclear abolitionist both behind the scenes and deep in his heart, in the view of author and academic Paul Lettow. His "Ronald Reagan and His Quest to Abolish Nuclear Weapons" has been raising major eyebrows in circles liberal as well as conservative and has been helping generate a sense of national unease about the defects of our non-proliferation policy and the lack of a serious nuclear-reduction/disarmament policy.

The newly aroused anti-nuclear campaign in America has been joined with octogenarian vehemence by Robert McNamara, now 89 no less. The former defense secretary in the Kennedy and Johnson administrations, has in newspaper interviews and op-ed essays been a one-man band warning of the inherent (or, as he puts it, "insane") dangers of so many ready-to-blow nukes in so many countries. His regrets about the Vietnam War and his unmistakable intellect have added a touch of establishment credibility to the abolitionist position.

This has enhanced the credibility of enduring firebrands like Helen Caldicott, the near-legendary Australian physician who has all but dedicated her life to the anti-nuclear campaign. Take a look, for illustration, at the astoundingly energetic Web site of the Nuclear Age Peace Foundation (www.wagingpeace.org), with whom Caldicott and many others are allied.

There's a feeling in the air that the anti-nuclear movement is gaining traction. The war in Iraq is obviously going badly and the hawks and neo-cons in Washington, if not exactly in retreat, seem not to be pounding their chests with such prideful arrogance these days. The recent endless United Nations summit-retreat on advancing the venerable Non-Proliferation Treaty was a colossal and embarrassing failure. The United States — which has brutally tabled the Comprehensive Test Ban Treaty and even raised the probability of funding further nuclear-weapons research — refuses to conform to the NPT's call for drawing down existing nuclear arsenals.

As Alyn Ware of the Lawyers Committee on Nuclear Policy has put it, "... It is impossible to prevent nuclear proliferation while the nuclear-weapons states insist on maintaining large stockpiles of weapons themselves. It's like a parent telling a child to not smoke while smoking a pack of cigarettes in their face. It's not going to work. ... "

The smoking gun is North Korea. We have invaded a country that possessed no weapons of mass destruction at the cost of more than 1,700 U.S. lives, unknown U.S. treasure and countless Iraqi lives, while fumbling big-time as Pyongyang played hardball on the nuclear issue. We have obviously got our national security-policy priorities upside down.

Thus we desperately need those fearless non-governmental organizations like the Nuclear Age Peace Foundation — not to mention old warriors like McNamara and Caldicott — to continue to campaign tirelessly if we are not to realize the kind of nuclear calamity that, present trends unchecked, seems increasingly predictable.

UCLA professor Tom Plate, a member of the Pacific Council on International Policy, is founder and director of UCLA's Media Center.